Butenolide Derivatives with α-Glucosidase Inhibitions from the Deep-Sea-Derived Fungus Aspergillus terreus YPGA10

Three new butenolide derivatives, namely aspernolides N–P (1–3), together with six known analogues (4–9), were isolated from the ethyl acetate (EtOAc) extract of the deep sea-derived fungus Aspergillus terreus YPGA10. The structures of compounds 1–3 were determined on the basis of comprehensive analyses of the nuclear magnetic resonance (NMR) and mass spectroscopy (MS) data, and the absolute configurations of 1 and 2 were determined by comparisons of experimental electronic circular dichroism (ECD) with calculated ECD spectra. Compound 1 represents the rare example of Aspergillus-derived butenolide derivatives featured by a monosubstituted benzene ring. Compounds 6–9 exhibited remarkable inhibitory effects against α-glucosidase with IC(50) values of 3.87, 1.37, 6.98, and 8.06 μM, respectively, being much more active than the positive control acarbose (190.2 μM).